This invention relates to methods of flocculating, accelerating the rate of flocculation and/or accelerating the settling of solids which are suspended in aqueous media by addition thereto of a flocculating composition.
U.S. Pat. No. 4,450,092 discloses compositions useful for coagulating finely divided solids in turbid waters. These compositions are prepared by mixing inorganic water-soluble compounds such as aluminum chloride, aluminum sulfate, ferric chloride and ferric sulfate with a polymer of diallyl dimethyl ammonium chloride having a molecular weight of at least 2,000. The weight ratio of the inorganic component to the organic component ranges from 0.75:1 to about 4:1.
U.S. Pat. No. 4,582,627 discloses flocculating agents which are reaction products of sulfate ion-containing polymeric aluminum hydroxy chloride and one or more cationic polymers such as polyacrylic amide, polyamide amine and polyethylene imine.
U.S. Pat. No. 4,137,165 discloses the use of low molecular weight acrylamide polymers which contain quaternized dimethylamino methyl groups for clarification of turbid waters.
U.S. Pat. No. 3,489,681 discloses the use of water-soluble copolymers of diacetone acrylamide as flocculating agents.
The term flocculation, as used herein, is synonymous with the term coagulation. Flocculation refers to the settling of suspended solid particles from aqueous systems. Turbidity, as used herein, is defined as the cloudiness or haziness of a solution caused by finely suspended particles. Turbidity is meausred using NTU's, (nephelometric turbidity units). As used herein, low turbidity systems are systems having a low solids concentration (on a weight basis), i.e., a solids weight percent of 0.1 or less. As a general rule, this corresponds to an approximate turbidity of 50 NTU's or less, but may vary do to nature of the solids or dissolved colored matter. High solids suspensions include those systems containing in excess of 0.1 weight percent suspended solids, which generally corresponds to a turbidity of greater than 50 NTU's. While the instant compositions are especially effective in low turbidity waters, it is not intended that their use be so restricted. In fact, the instant compositions are useful in a wide variety of raw waters and in concentrated wastewaters.
Many flocculants are known, including alum (Al.sub.2 (SO.sub.4).sub.3 X H.sub.2 O, wherein X is about 14), poly(aluminum chloride), sodium aluminate, iron compounds such as ferric chloride and ferric sulfate, lime and various cationic organic polymers, including but not limited to poly(alkaline amines), poly(diallyl dimethyl ammonium chloride), poly(2-hydroxy propyl-1-N-methyl ammonium chlorides) and quaterized poly(N-N-dimethylaminomethacrylate). The novel compositions of the instant invention are not, however, known or suggested in the art.